Boron trifluoride etherate → 4-Hydroxy-3-(3-methyl-1-phenylbutyl)-2H-1-benzopyran-2-one

HRID 2293670Notes

Reaction equation

HRID 2293670 reaction equation
[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][C:4](=[O:12])[CH:3]=1.[CH3:13][CH:14]([CH3:24])[CH2:15][CH:16]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)O.B(F)(F)F.CCOCC>O1CCOCC1>[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][C:4](=[O:12])[C:3]=1[CH:16]([C:18]1[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=1)[CH2:15][CH:14]([CH3:24])[CH3:13]

Participants

5

Reactant 3

HCID 8000Boron trifluoride etherateHCID 12487504α-(2-Methylpropyl)benzenemethanolHCID 546829304-Hydroxycoumarin

Product 1

HCID 547114904-Hydroxy-3-(3-methyl-1-phenylbutyl)-2H-1-benzopyran-2-oneYield 20.1%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

To a time-dried flask containing a near-solution of 650 mg of 4-hydroxycoumarin and 800 mg of 3-methyl-1-phenylbutan-1-ol of Preparation 16 in 25 mL of dioxane under an argon atmosphere is added 2.5 mL of boron trifluoride etherate. The resulting yellow solution is left to stir at room temperature. After 3 days the volatiles are removed and the residue is partioned between diethyl ether and 1N sodium hydroxide. The basic aqueous phase is washed with diethyl ether and acidified to pH=1 with 6N hydrochloric acid. The resulting precipitant is repeatedly extracted with dichloromethane (methanol-chloroform Co-solvents). The combined dichloromethane extracts are washed once with dilute sodium bicarbonate to remove most of the unreacted 4-hydroxycoumarin, then brine, dried (magnesium sulfate), and finally concentrated under reduced pressure. The residue is adsorbed onto silica and flash column chromatographed with 30% to 40% ethyl acetate in hexane to yield 248 mg of the title product as a white solid.

Workup

  1. additionTo a time-dried flask containing
  2. waitThe resulting yellow solution is left
  3. customAfter 3 days the volatiles are removed
  4. washThe basic aqueous phase is washed with diethyl ether
  5. extractionThe resulting precipitant is repeatedly extracted with dichloromethane (methanol-chloroform Co-solvents)
  6. washThe combined dichloromethane extracts are washed once with dilute sodium bicarbonate
  7. customto remove most of the unreacted 4-hydroxycoumarin
  8. dry with materialbrine, dried (magnesium sulfate)
  9. concentrationfinally concentrated under reduced pressure
  10. customchromatographed with 30% to 40% ethyl acetate in hexane

Sources & evidence

ORD record
ord-897c59db97db469cbf16ecfa1186c243
Source dataset
uspto-grants-1997_11
Patent number
US05686486

Reaction notes

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